The maximum lethality of the 40 mm anti-personnel cartridge, having a round which includes a fragmenting sphere, depends upon its sensitivity to impact. In those applications where the impacting area for the round will be on a relatively hard surface as earth, stone, concrete, a vehicle, no significant problems have occurred with prior art devices, they have functioned well producing an air burst of the fragmenting sphere or envelope with uniform dispersal of the lethal fragments. Problems have arisen in the use of these anti-personnel munitions where the striking surface is likely to be soft snow. Prior art devices which have their impact actuation mechanisms designed to be sensitive to soft snow impact or graze impact have been found to be also sensitive to activation by rain drops. Such prior art devices which are activated by coming in contact with rain are unsatisfactory because they endanger the launching personnel. Those prior art impact devices which are insensitive to rain and wind generally will also be insensitive to snow impact. Where the snow is deep this insensitivity results in the round burying itself below the surface before explosion with a consequent loss in effectiveness.
The present device is an actuator assembly which provides an operational capability for 40 mm cartridges, having anti-personnel rounds, capable of functioning when impacting on a surface of soft snow. The present actuator assembly device is particularly useful for medium round ammunition such as the 40 mm cartridge because it can be made small in size, and is relatively inexpensive because of its simple and rugged construction.